医院水环境军团菌污染及住院肺炎病例军团菌感染来源调查

Contamination status of Legionella in hospital water environment and traceability of Legionella infection in hospitalized pneumonia cases

目的了解医院水环境军团菌污染及住院肺炎病例军团菌感染来源。方法采集医院冷却塔水和管网末梢水共24件,进行军团菌分离培养。对90例住院肺炎病例进行问卷调查、深部痰液军团菌培养和荧光定量PCR检测、军团菌尿抗原和血抗体检测,明确军团菌发病情况及类型。对分离环境菌株和病人菌株进行了PFGE和SBT检测,进行病原体溯源。结果医院冷却塔水军团菌阳性率100%(5/5),其中有2份水样军团菌浓度大于103cfu/L;管网末梢水军团菌阳性率21.1%(4/19),其中有3份水样军团菌浓度大于103cfu/L。余氯量平均0.03 mg/L,污染军团菌血清型LP1、LP6。住院肺炎病例中军团菌肺炎阳性率15.6%(14/90),其中痰培养和PCR同时阳性1例、尿抗原阳性13例,社区获得性军团菌肺炎16.4%(11/67)、医院获得性军团菌肺炎20.0%(3/15)。分离环境与病人菌株血清型别和PFGE图谱分析均不一致,未能溯源。结论医院水环境军团菌污染严重且污染浓度高,余氯浓度低于标准,存在发生医院内军团菌肺炎甚至暴发流行的严重隐患。建议定期监测医院水环境军团菌,对医院肺炎病人进行军团菌病相关检测,并研究具有可行性的消毒措施去除军团菌污染。

Objective To investigate the contamination status of Legionella in hospital water environment and traceability of Legionella infection in hospitalized pneumonia cases. Methods Twenty- four cooling tower water and tap water samples were collected from a hospital for Legionella test and quantitative culture. To know the situation and types of Legionella infection in the hospital, we surveyed 90 hospitalized pneumonia cases through questionnaire investigation, deep sputum culture and fluorescence quantitative PCR detection as well as urinary antigen and serum antibody detection . Legionella strains isolated from the hospital environment and from the cases were tested by pulse field gel electrophoresis （PFGE） and sequence- based typing （SBT） to learn the source of Legionella infection. Results The positive rate of Legionella in the cooling tower water of the hospital was 100% （5/5）, and Legionella counts of 2 samples were both higher than 103 cfu/L. The positive rate of Legionella in the tap wa- ter samples of the hospital was 21.1% （4/19）, and Legiondla counts of 3 samples were higher than 103 cfu/L. The average of residual chlorine in the water was 0.03 mg/L. The serotypes of Legionella in the polluted water included LP1 and LP6. 15.6% （14/90） hospitalized pneumonia cases were infected with Legionella, of which one case had positive results both in sputum culture and PCR assay, and 13 cases had positive urinary antigens . 16.4 % （11/67） cases got community acquired legionellosis, while 20.0% （3/15）got hospital acquired legiondlosis. Serotypes and PFGE spectra of the strains separated from the water samples and patients were inconsistent; and hence, the source of Legionella infection was unclear. Conclusions Severe contamination and high concentration of Legionella exist in the water environment of the hospital investigated and residual chlorine concentration is lower than that of the standard, which may cause the occurrence or even outbreaks of hospital - acquired legionellosis. We sug-gest regularly monitoring Legionella in hospital water environment and performing Legionella disease related detection in hospitalized pneumonia cases; moreover, disinfection of the water systems to remove Legionella contamination should be considered.